JQuery Event Add [source analysis]

/* Helper functions for managing events – not part of the public interface. * Props to Dean Edwards ' addevent Library for many of the ideas. */jquery.event = {Add:function (elem, types, handler, data, selector) {var elemdata, Eventhandle, Events,t, TNS, type, n Amespaces, Handleobj,handleobjin, quick, handlers, special;//Don ' t attach events to NoData or Text/comment nodes (allow P Lain objects Tho) if (elem.nodetype = = = 3 | | elem.nodetype = = 8 | |!types | |!handler | |! ( Elemdata = Jquery._data (elem)) {return;} Caller can pass in a object of custom data in lieu of the handler//here in the past has not understood why to do so, the reason is that the handler here can be a function, that we Usually said the binding event method//can also be an event object, that is, the following handleobj, then if it is inside the jquery can be passed an event object come over if (handler.handler) {Handleobjin = Handler;handler = Handleobjin.handler;selector = Handleobjin.selector;}  Make sure, the handler have a unique ID, used to find/remove it later//assign Guidif (!handler.guid) {handler.guid = jquery.guid++;} Init the element ' s event struCture and main handler, if this is the first//from the caching system, gets the events array from the Cache event object, events = Elemdata.events;if (!events) {elemdata. Events = events = {};} The main listener function, the only method that binds to a DOM element, invokes dispatch assignment Event Eventhandle = elemdata.handle;if (!eventhandle) {elemdata.handle =  Eventhandle = function (e) {//Discard the second event of a jQuery.event.trigger () and//when an event was called after a Page has unloaded//here mainly to prevent the trigger manually triggered when the two times bubbling. Here in the trigger, there will be simulated bubbling events,//mainly for events that cannot be bubbling, such as: Focus can only simulate the bubbling event//If it has bubbled up, then there is no need to execute again. Return typeof jQuery!== "undefined" && (!e | | jQuery.event.triggered!== e.type)? jQuery.event.dispatch.apply (Ev Enthandle.elem, arguments): undefined;};/ /Add Elem as a property of the handle FN to prevent a memory leak with IE non-native events//here are mainly for IE memory problems eventhandle.el em = Elem;} Handle multiple events separated by a space//jQuery (...). Bind ("MouseOver mouseout", FN);//Cut multiple event combinations types = Jquery.trim (Hoverhack (types)). Split (""); for (t = 0; T < Types.length; t++) {//Use regular cutnamespace//rtypenamespace =/^ ([^\.] *)? (?:\. (.+))? $/,//such as: Click.namespace,hover.namespace//==> ["Click.namespace", "click", "namespace", index:0, Input: " Click.namespace "] TNS = Rtypenamespace.exec (types[t]) | | [];type = Tns[1];namespaces = (Tns[2] | | ""). Split ("."). Sort ();//If event changes its type with the special event handlers for the changed type//here mainly fixes the event to see if there is a definition in special, if Yes, I have just replaced the event type in special//mainly some native events, there is a compatibility problem with the browser, so we need to replace Special = jquery.event.special[Type] | | {};//If selector defined, determine special event API type, otherwise given type//here selector is a proxy event, if there is selector, then there is a bubbling thing Pieces//For delegatetype is mainly to replace the original can not bubble events such as: Focus and focusin//Then if the native event is not a problem for bubbling, then the detection of the binding type needs to be fixed: such as: MouseOver ==> MouseEnter type = (selector? special.delegateType:special.bindType) | | type;//Update Special based on newly reset typespecial = jquery.event.special[Type] | | {};//Handleobj is passed to all event Handlershandleobj = Jquery.extend ({type:type,origtype:tns[1],data:data,Handler:handler,guid:handler.guid,selector:selector,quick:selector && Quickparse (selector), namespace: Namespaces.join (".")}, Handleobjin);//Init the event handler queue if we ' re the firsthandlers = events[type];if (!han  dlers) {handlers = events[type] = [];handlers.delegatecount = 0;//only use addeventlistener/attachevent if the special Events Handler returns Falseif (!special.setup | | special.setup.call (elem, data, namespaces, eventhandle) = = = = False) {//Bind the global event handler to the Elementif (Elem.addeventlistener) {Elem.addeventlistener (type, Eventhandle, FA LSE);} else if (elem.attachevent) {elem.attachevent ("on" + Type, eventhandle);}}} if (special.add) {Special.add.call (Elem, handleobj); if (!handleobj.handler.guid) {handleObj.handler.guid = Handler.g UID;}} Add to the element's handler list, delegates in Frontif (selector) {handlers.splice (handlers.delegatecount++, 0, Han Dleobj);} else {Handlers.push (handleobj);} Keep track OF which events has ever been used, for event optimizationjquery.event.global[type] = true;} Nullify elem to prevent memory leaks in Ieelem = null;}

JQuery Event Add [source analysis]